The present invention relates to apparatus for producing color effects by selective color decomposition of polarized white light.
Certain media have the property of rotating the angle of polarization of polarized light as a function of wavelength. When polarized white (polychromatic) light passes through such a dispersive medium, the angle of polarization is rotated as a function of wavelength to thereby produce angular color separation of the polarized light. The white light is thus decomposed to the various colors of the spectrum, for example with the red light characterized by one polarization angle being at one end, and purple light characterized by another polarization angle being at the opposite end of the spectrum. The extent of separation, defined as the relative angle between the polarization angles for the two extremes of the visible spectrum, is dependent on: (1) the material of the dispersive medium; (2) the thickness of the dispersive medium; and (3) when the dispersive medium is anisotropic (having optical properties that differ according to the direction of measurement), also on the relative angle between the incident light polarization and the optical axis of the dispersive medium.